1. Field of the Invention
The present invention relates to a zoom lens and an imaging apparatus. More particularly, the present invention relates to an a zoom lens and an imaging apparatus having a so-called vibration-proof function in which a blur of a photographed image is optically corrected when vibrated to obtain an image free from a blur by moving a part of lens groups so as to have a component in a direction perpendicular to an optical axis, thereby resulting in stabilization of the photographed image, and further having a higher variable power ratio of about 15 to 20 times.
2. Description of Related Art
During photographing of an imaging apparatus, such as a still camera, a video camera and the like, for example, the occurrence of camera shake attributed to shutter operation or shake caused by transmitting vibration to a photographing system when a subject is photographed from a moving object such as a car results in a blur on a photographed image. As means for correcting the above-described image blur resulting from the camera shake, there has been known a shake-correcting optical system that by moving (shifting) a part of lens groups making up a lens system in a direction substantially perpendicular to an optical axis, displaces an image position to correct the image blur, and also corrects deterioration in optical performance occurring when the image position is displaced.
As the above-described camera shake-correcting optical system, for example, there is one described in Japanese Patent Application Laid-Open No. 2006-98963, Patent Document 1. In a shake-correcting optical system described in Patent Document 1, a zoom lens includes first to fourth lens groups having positive, negative, positive, and positive refractive powers, respectively, and a fifth lens group made up of a negative part group having a negative refractive power and a positive part group having a positive refractive power. These first to fifth lens groups are arrayed in order from the object side to the image side, and the positive part group of the fifth lens group is moved in the direction substantially perpendicular to the optical axis to thereby perform vibration control.